Heating Repair in Southern NH
No Heat? Start Here
When the heat quits in a New Hampshire winter, you need the real fault found and fixed, not parts swapped until something works. Jolt Electric & HVAC repairs furnaces, boilers, and steam systems on oil, natural gas, propane, and electric, plus heat pumps and ductless mini splits, from Nashua and Manchester to Hudson, Merrimack, and Londonderry.
We've repaired heating systems across Southern New Hampshire for over 30 years, we're licensed and insured, and we're based in Litchfield. Because we're an electrical contractor too, a tripped breaker, a dead transformer, or a wiring fault is ours to diagnose and fix, with no second contractor to call.
Signs Your Heating System Needs Repair
Installation, Maintenance & Repair
Contact us if you notice:
• No heat, weak heat, or rooms that never catch up
• Radiators or baseboard that stay cold while the boiler runs
• Banging, rattling, squealing, or gurgling
• A gas or propane flame burning yellow or orange instead of blue
• Soot on or around the burner, or an oil or exhaust smell
• Short cycling, lockouts, or a system you keep resetting
• Water, rust, or a dripping relief valve around the boiler
• Fuel use rising while the weather hasn't changed
If the system has locked out, press the reset button once. On an oil burner every extra press pumps more oil into the chamber, and that can cause a puffback when it finally lights. If it won't stay running after one reset, leave it off and get in touch.
When to Shut It Off and Get Out
A rotten egg or sulfur smell means gas. Get everyone out of the building, and don't flip switches, unplug anything, or use a phone until you're outside and well away. Call 911 or the gas company's emergency line from there, and stay out until they say it's safe. A sounding CO alarm gets the same response: everyone out, then call 911 from outside. Once the building's cleared, we'll handle the repair.
Carbon monoxide has no color or smell, and a cracked heat exchanger or a dirty burner can produce it. Keep working CO alarms on each floor and outside the bedrooms.
Before You Contact Us
A few checks take two minutes. Make sure the thermostat is set to heat and has fresh batteries, the furnace or burner switch is on (on oil systems it's often a red switch at the top of the basement stairs), the breaker hasn't tripped, and the filter isn't clogged. On oil or propane, check that the tank isn't empty. If all of that checks out, the rest needs a technician.
Commercial Generators
Parking Lot Lighting
EV Chargers
Commercial Tenant Fit-ups
Electrical Panel Upgrades
LED Lighting Upgrades
Commercial Smoke, Fire, and CO Detectors
Furnace, Boiler, Steam, and Heat Pump Repairs We Handle
Installation, Maintenance & Repair
We don't start with parts. Every repair visit traces the call for heat from the thermostat through ignition, airflow or circulation, power, and the safety controls, so the part we replace is the one that failed. You hear what failed, what the fix involves, and the price before we start.
Furnaces
Gas and propane furnaces usually fail at the ignitor, the flame sensor, the gas valve, or a safety switch that trips when airflow drops. Oil furnaces usually fail in the fuel train: the pump, the nozzle, or ignition. Electric furnaces usually lose a heating element or a sequencer. Blower motors, capacitors, and control boards can take down any of them.
Boilers and Hot Water Heat
We repair oil, gas, propane, and electric boilers: circulator pumps, zone valves, expansion tanks, relief valves, low-water cutoffs, aquastats, primary controls, and venting. A cold zone on a boiler that's running is usually air, flow, or a stuck zone valve, not the boiler itself.
Steam Heat
One-pipe and two-pipe steam, in homes and in the older schools, churches, and commercial buildings that still run it. Most steam complaints are piping, venting, or pressure problems rather than boiler problems, so we diagnose the whole system before we touch the boiler.
Heat Pumps and Ductless Mini Splits
A heat pump, ducted or ductless, loses some output in deep cold by design, and a short defrost cycle that blows cool air is normal. When one stops keeping up altogether, ices over and never clears, or runs without warming the house, the fault is usually in the outdoor unit, the defrost cycle, the refrigerant charge, or the controls.
Oil, Natural Gas, and Propane
Each fuel has its own diagnostic path, and we work on all three, gas piping included under our own New Hampshire gas license.
Licensed Fuel Gasfitters in NH
Unlike many HVAC companies, we hold a New Hampshire Fuel Gasfitters License, which saves you both time and money.
One Company, One Call
You don’t need to hire a separate contractor for your fuel gas connection.
Faster Installations
You save time with a streamlined installation process.
Peace of Mind
You know your heating installation is safe and complies with all state regulations.
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Repair or Replace: What Decides It
Heating Installation, Maintenance & Repair
Four things decide whether we repair or replace: how old the system is, how often it has failed, whether it's still safe, and what this repair costs against what's left in the equipment. One failed part on a system with years left is a repair. A third no-heat call in two winters on a worn-out one is a replacement conversation.
A boiler is easier to call. We clean it, run a combustion test, and look at the block. Good numbers on a sound block mean keep it. A cracked or weeping block, or efficiency that won't recover after cleaning, means replace it. A cast iron boiler can outlast 30 winters, so age by itself never decides it.
If a repair makes sense, that's what we recommend, and we say so. If it doesn't, we explain why, and a replacement gets sized from a heat loss calculation, not copied off the old nameplate.
Heating Repair FAQ
Why is my furnace running but blowing cold air?
Check the thermostat fan setting first. If it's set to On instead of Auto, the blower runs whether or not the burner is lit. If that's not it, a clogged filter, a dirty flame sensor, or a failed ignitor can each keep the burner off while the fan keeps going.
Why is one radiator cold when the rest of the house is warm?
On hot water heat it's usually air trapped in that radiator or a zone valve that's stuck. On one-pipe steam it's usually the radiator's air vent, because air has to leave before steam can get in. Turning up the boiler pressure won't fix it and usually makes it worse.
Do you repair heating systems in commercial buildings?
Yes. Along with homes, we repair commercial boilers and multi-boiler plants, rooftop units, and steam heat in schools, churches, and larger buildings.
Which towns do you cover for heating repair?
We're based in Litchfield and repair heating systems in Nashua, Manchester, Hudson, Merrimack, Londonderry, Amherst, Bedford, Hollis, Milford, Derry, Goffstown, Salem, and Windham.
Jolt Electric & HVAC holds New Hampshire Mechanical Business Entity Gas License MBE1901198.
What Our Customers Say
At Jolt Electric & HVAC, we take pride in delivering top-quality workmanship and reliable service to every client. See what our satisfied customers have to say about working with us.
Request an Estimate
Whether you need electrical, heating, or cooling services, Jolt Electric is here to help. Our team is dedicated to delivering high-quality work, transparent pricing, and unparalleled customer service to homeowners and businesses throughout New Hampshire.
Service Area:
We proudly serve homeowners and businesses throughout Southern New Hampshire, including Litchfield, Nashua, Londonderry, Milford, Merrimack, Hudson, Manchester, Amherst, Hollis, and Bedford.